The transcriptional response to androgens of the rat VCSA1 gene is amplified by both binary and graded mechanisms

Extended abstinence from morphine alters sperm smRNA expression and prevents transmission of intergenerational phenotypes

Paternal exposure to drugs of abuse can impact addiction-related behaviours in progeny via germline epigenome remodelling. Previously, we found that offspring of morphine-exposed male rats showed increased morphine-taking, diminished adolescent social play, and increased sensitivity to morphine-derived analgesia. Here, we first tested the impact of a 90-day paternal abstinence period following morphine self-administration on the transmission of the aforementioned phenotypes. The previously observed changes in morphine-related behaviours were no longer present in offspring of morphine-abstinent sires. We next compared small RNA (smRNA) content in sperm collected from four sire intravenous self-administration groups: morphine, saline, abstinent morphine, and abstinent saline. Two smRNAs (rno-miR-150-5p and an snoRNA annotated to Snora42/Noc3l) were differentially expressed specifically between morphine- and saline-treated sperm. No differential expression between abstinent morphine and saline sperm was observed. These data begin to delineate the temporal limits of heritable germline modifications associated with morphine exposure, in addition to identifying F0 germline factors coinciding with the manifestation of F1 multigenerational phenotypes. Furthermore, these data suggest that paternal abstinence at conception can prevent inheritance of germline factors that may alter offspring susceptibility to addiction-related endophenotypes.

Opiorphin in burning mouth syndrome patients: a case-control study

OBJECTIVES

Opiorphin is a pentapeptide isolated from human saliva that suppresses pain from chemically induced inflammation and acute physical pain. Burning mouth syndrome (BMS) is a chronic condition of a burning sensation in the mouth, where no underlying dental or medical cause can be identified. We aimed to measure the level of opiorphin in whole unstimulated (UWS) and stimulated (SWS) saliva of patients with BMS.

MATERIALS AND METHODS

Originally developed and validated LC-MS/MS method was used for opiorphin quantification. Samples were obtained from 29 BMS patients and 29 age- and sex-matched controls.

RESULTS

The average concentration of opiorphin in UWS and SWS in the BMS group was 8.13 ± 6.45 and 5.82 ± 3.59 ng/ml, respectively. Opiorphin in BMS patients' UWS was significantly higher, compared to the control group (t = 2.5898; p = 0.0122). SWS opiorphin levels were higher, but not significantly, in BMS patients than in controls.

CONCLUSIONS

Our results indicate that higher quantities of salivary opiorphin in BMS may be a consequence of chronic pain, but we cannot exclude that they occur as a result of emotional and behavioral imbalances possibly associated with BMS. To our knowledge, this is the first original article measuring opiorphin in a pain disorder.

CLINICAL RELEVANCE

Opiorphin may be a measurable biomarker for chronic pain, which could help in objectifying otherwise exclusively a subjective experience. Increased opiorphin could serve as a universal objective indicator of painful conditions. Since opiorphin may also reflect emotional and socio-relational imbalances occurring with BMS, it could as well represent a biomarker for BMS. Knowledge on opiorphin's involvement in pain pathways could contribute to developing new clinical diagnostic methods for BMS.

Salivary gland derived peptides as a new class of anti-inflammatory agents: review of preclinical pharmacology of C-terminal peptides of SMR1 protein

The limitations of steroidal and non steroidal anti-inflammatory drugs have prompted investigation into other biologically based therapeutics, and identification of immune selective anti-inflammatory agents of salivary origin. The traditional view of salivary glands as accessory digestive structures is changing as their importance as sources of systemically active immunoregulatory and anti-inflammatory factors is recognized. Salivary gland involvement in maintenance of whole body homeostasis is regulated by the nervous system and thus constitutes a "neuroendocrine axis". The potent anti-inflammatory activities, both in vivo and in vitro, of the tripeptide Phe-Glu-Gly (FEG) are reviewed. FEG is a carboxyl terminal peptide of the prohormone SMR1 identified in the rat submandibular salivary gland, The D-isomeric form (feG) mimics the activity of its L-isomer FEG. Macropharmacologically, feG attenuates the cardiovascular and inflammatory effects of endotoxemia and anaphylaxis, by inhibition of hypotension, leukocyte migration, vascular leak, and disruption of pulmonary function and intestinal motility. Mechanistically, feG affects activated inflammatory cells, especially neutrophils, by regulating integrins and inhibiting intracellular production of reactive oxygen species. Pharmacodynamically, feG is active at low doses (100 μg/kg) and has a long (9-12 hour) biological half life. As a therapeutic agent, feG shows promise in diseases characterized by over exuberant inflammatory responses such as systemic inflammatory response syndrome and other acute inflammatory diseases. Arthritis, sepsis, acute pancreatitis, asthma, acute respiratory inflammation, inflammatory bowel disease, and equine laminitis are potential targets for this promising therapeutic peptide. The term "Immune Selective Anti-Inflammatory Derivatives" (ImSAIDs) is proposed for salivary-derived peptides to distinguish this class of agents from corticosteroids and nonsteroidal anti-inflammatory drugs.

The mechanism of opiorphin-induced experimental priapism in rats involves activation of the polyamine synthetic pathway

Intracorporal injection of plasmids encoding opiorphins into retired breeder rats can result in animals developing a priapic-like condition. Microarray analysis demonstrated that following intracorporal gene transfer of plasmids expressing opiorphins the most significantly upregulated gene in corporal tissue was the ornithine decarboxylase gene (ODC). Quantitative RT-PCR confirmed the upregulation of ODC, as well as other genes involved in polyamine synthesis, such as arginase-I and -II, polyamine oxidase, spermidine synthase, spermidine acetyltransferase (SAT), and S-adenosylmethionine decarboxylase. Western blot analysis demonstrated upregulation of arginase-I and -II, ODC, and SAT at the protein level. Levels of the polyamine putrescine were upregulated in animals treated with opiorphin-expressing plasmids compared with controls. A direct role for the upregulation of polyamine synthesis in the development of the priapic-like condition was supported by the observation that the ODC inhibitor 1,3-diaminopropane, when added to the drinking water of animals treated with plasmids expressing opiorphins, prevented experimental priapism. We also demonstrate that in sickle cell mice, another model of priapism, there is increased expression of the mouse opiorphin homologue in corporal tissue compared with the background strain at a life stage prior to evidence of priapism. At a life stage when there is onset of priapism, there is increased expression of the enzymes involved in polyamine synthesis (ODC and arginase-I and -II). Our results suggest that the upregulation of enzymes involved in the polyamine synthetic pathway may play a role in the development of experimental priapism and represent a target for the prevention of priapism.

Testosterone regulates erectile function and Vcsa1 expression in the corpora of rats

Vcsa1 plays an important role in the erectile physiology of the rat. We conducted experiments to determine if erectile function, testosterone levels and Vcsa1 expression were correlated. In orchiectomized rats, total testosterone in blood fell from an average of 4 ng/ml to <0.04 ng/ml. Erectile function was significantly lower compared to controls and Vcsa1 expression was significantly (>6-fold) decreased. Injection of orchiectomized animals with testosterone (2 mg in 100ml sesame oil every 4 days for 2 weeks) restored average levels of testosterone to 2 ng/ml, increased erectile function and significantly increased Vcsa1 expression. In isolated corporal cells there was testosterone dependent Vcsa1 expression. However, intracorporal injection of orchiectomized animals with a plasmid expressing Vcsa1 or its gene product Sialorphin (previously demonstrated to improve erectile function in old animals) gave no significant improvement in erectile function. Also, the ability of Sialorphin to reduce tension in corporal smooth muscle strips isolated from orchiectomized animals was impaired compared to controls.

The role of opiorphins (endogenous neutral endopeptidase inhibitors) in urogenital smooth muscle biology

INTRODUCTION

The opiorphins are a newly characterized class of peptides that act as potent endogenous neutral endopeptidase (NEP) inhibitors. Recent reports have suggested that they play an important role in erectile physiology.

AIM

This article reviews recent developments that increase our understanding of the role of the opiorphin family of peptides in erectile physiology.

METHODS

During a microarray screen of gene changes that occur in a rat diabetic model of erectile dysfunction (ED), Vcsa1 was one of the most down-regulated genes in the rat corpora. Quantitative real-time polymerase chain reaction demonstrated that in at least three models of diseases that result in ED (diabetes, aging, and cavernous nerve [CN] transection), Vcsa1 was down-regulated in the rat corpora. The human opiorphin family of genes (hSMR3A/B and ProL1) also acts as markers of erectile function in patients with ED.

MAIN OUTCOME MEASURES

The reader will be informed of the most current research regarding the role of opiorphins in urogenital smooth muscle biology.

RESULTS

These observations led to the suggestion that genes encoding opiorphins (and potentially their peptide products) can act as markers of ED. Gene transfer of plasmids overexpressing Vcsa1 in aging rats, as well as intracorporal injection of sialorphin, led to an improvement in erectile function. In organ bath studies, we demonstrated that sialorphin can cause increased rates of relaxation of corporal smooth muscle (CSM). We have also demonstrated that in vitro, Vcsa1 causes changes in the expression of G-protein-coupled receptors (GPCRs). This has led us to suggest that the action of Vcsa1 on erectile physiology may act through relaxation of CSM by its ability to act as an inhibitor of NEP, therefore prolonging the action of peptide agonists at their GPCRs.

CONCLUSIONS

Overall, there is a growing body of evidence that the opiorphins play a role in regulating CSM tone and thereby erectile function.

The opiorphin gene (ProL1) and its homologues function in erectile physiology

OBJECTIVE

To determine if ProL1, a member of the opiorphin family of genes, can modulate erectile physiology, as it encodes a peptide which acts as a neutral endopeptidase inhibitor, other examples of which (Vcsa1, hSMR3A) modulate erectile physiology.

MATERIALS AND METHODS

We cloned members of the opiorphin family of genes into the same mammalian expression backbone (pVAX); 100 microg of these plasmids (pVAX-Vcsa1, -hSMR3A, -hSMR3B and -ProL1) were injected intracorporally into retired breeder rats and the affect on erectile physiology assessed visually, by histology and by measuring the intracavernous pressure (ICP) and blood pressure (BP). As a positive control, rats were treated with pVAX-hSlo (expressing the MaxiK potassium channel) and as a negative control the empty backbone plasmid was injected (pVAX). We also compared the level of expression of ProL1 in corporal tissue of patients not reporting erectile dysfunction (ED), ED associated with diabetes and ED not caused by diabetes.

RESULTS

Gene transfer of plasmids expressing all members of the opiorphin family had a similar and significant effect on erectile physiology. At the concentration used in these experiments (100 microg) they resulted in higher resting ICP, and histological and visual analysis showed evidence of a priapic-like condition. After electrostimulation of the cavernous nerve, rats had significantly better ICP/BP than the negative control (pVAX). Gene transfer of pVAX-hSlo increased the ICP/BP ratio to a similar extent to the opiorphin homologues, but with no evidence for a priapic-like condition. Corpora cavernosa tissue samples obtained from men with ED, regardless of underlying causes, had significant down-regulation of both hSMR3A and ProL1.

CONCLUSION

All members of the human opiorphin family of genes can potentially modulate erectile physiology. Both hSMR3 and ProL1 are down-regulated in the corpora of men with ED, and therefore both genes can potentially act as markers of ED.

Comparative anti-androgenic actions of vinclozolin and flutamide on transgenerational adult onset disease and spermatogenesis

Exposure of gestating female rats to the anti-androgenic endocrine disruptor vinclozolin has been shown to induce transgenerational adult onset disease phenotypes. The current study, was designed to compare the actions of vinclozolin to the known anti-androgenic compound flutamide. The gestating female rats were exposed to intraperitoneal injections during embryonic day 8-14 (E8-E14) to 100mg/kg/day vinclozolin or flutamide at either 5mg or 20mg/kg/day. As previously observed, vinclozolin induced a transgenerational testis phenotype of increased spermatogenic cell apoptosis and decreased epididymal sperm number. In contrast, the flutamide exposures resulted in a testis phenotype of increased spermatogenic cell apoptosis and decreased epididymal sperm numbers in the F1 generation only, and not the F2 and F3 generation adult males. Interestingly, some of the low dose (5mg/kg) flutamide F2 generation offspring developed spinal agenesis and supernummery development (polymelia) of limbs. Although the actions of vinclozolin and flutamide appear similar in the F1 generation males, the transgenerational effects of vinclozolin do not appear to be acting through the same anti-androgenic mechanism as flutamide.

hSMR3A as a marker for patients with erectile dysfunction

PURPOSE

We recently reported that Vcsa1 is one of the most down-regulated genes in the corpora of rats in 3 distinct models of erectile dysfunction. Since gene transfer of plasmids expressing Vcsa1 or intracorporeal injection of its mature peptide product sialorphin into the corpora of aging rats was shown to restore erectile function, we proposed that the Vcsa1 gene has a direct role in erectile function. To determine if similar changes in gene expression occur in the corpora of human subjects with erectile dysfunction we identified a human homologue of Vcsa1 (hSMR3A) and determined the level of expression of hSMR3A in patients.

MATERIALS AND METHODS

hSMR3A was identified as a homologue of Vcsa1 by searching protein databases for proteins with similarity. hSMR3A cDNA was generated and subcloned into the plasmid pVAX to generate pVAX-hSMR3A. pVAX-hSMR3A (25 or 100 microg) was intracorporeally injected into aging rats. The effect on erectile physiology was compared histologically and by measuring intracorporeal pressure/blood pressure with controls treated with the empty plasmid pVAX. Total RNA was extracted from human corporeal tissue obtained from patients undergoing previously scheduled penile surgery. Patients were grouped according to normal erectile function (3), erectile dysfunction and diabetes (5) and patients without diabetes but with erectile dysfunction (5). Quantitative reverse-transcriptase polymerase chain reaction was used to determine the hSMR3A expression level.

RESULTS

Intracorporeal injection of 25 microg pVAX-hSMR3A was able to significantly increase the intracorporeal pressure-to-blood pressure ratio in aging rats compared to age matched controls. Higher amounts (100 microg) of gene transfer of the plasmid caused less of an improvement in the intracorporeal pressure-to-blood pressure ratio compared to controls, although there was histological and visual evidence that the animals were post-priapitic. These physiological effects were similar to previously reported effects of intracorporeal injection of pVAX-Vcsa1 into the corpora of aging rats, establishing hSMR3A as a functional homologue of Vcsa1. More than 10-fold down-regulation in hSMR3A transcript expression was observed in the corpora of patients with vs without erectile dysfunction. In patients with diabetes associated and nondiabetes associated erectile dysfunction hSMR3A expression was found to be down-regulated.

CONCLUSIONS

These results suggest that hSMR3A can act as a marker for erectile dysfunction associated with diabetic and nondiabetic etiologies. Given that our previous studies demonstrated that gene transfer of the Vcsa1 gene and intracorporeal injection of its protein product in rats can restore erectile function, these results suggest that therapies that increase the hSMR3A gene and product expression could potentially have a positive impact on erectile function.

Sialorphin (the mature peptide product of Vcsa1) relaxes corporal smooth muscle tissue and increases erectile function in the ageing rat

OBJECTIVE

To determine if the mature peptide product of the Vcsa1 gene, sialorphin, could restore erectile function in ageing rats, and whether these effects are mediated through relaxation of corporal smooth muscle tissue, as we recently reported that Vcsa1 is one of the most down-regulated genes in the corpora of rats in three distinct models of erectile dysfunction, and gene transfer of plasmids expressing Vcsa1 into the corpora of ageing rats restored erectile function.

MATERIALS AND METHODS

Sialorphin was injected intracorporeally into retired breeder rats, and the effect on the physiology of corporal tissue was analysed by intracorporal/blood pressure (ICP/BP) measurement at different times after injection. In organ-bath studies, the ability of sialorphin (1 microg/mL) to enhance C-type natriuretic peptide (CNP) relaxation of corporal smooth muscle tissue strips was investigated after pre-contraction with 1 microm phenylephrine.

RESULTS

Intracorporal injection of 100 microg sialorphin into retired breeder rats resulted in a time-dependent increase in the ICP/BP response to electrostimulation of the cavernosal nerve. After 55-65 min the ICP/BP ratio increased to approximately 0.6, a value associated with normal erectile function. In organ-bath studies after pre-contraction with 1 microm phenylephrine, 1 microm CNP significantly (67%) increased the relaxation rate of corporal tissue. This rate of relaxation was increased by 2.5-fold after incubation with sialorphin (1 microg/mL) compared with carrier alone.

CONCLUSION

These results show that sialorphin has a role in erectile function, probably through a mechanism that involves relaxation of corporal smooth muscle tissue.

Human Opiorphin, a natural antinociceptive modulator of opioid-dependent pathways

Mammalian zinc ectopeptidases play important roles in turning off neural and hormonal peptide signals at the cell surface, notably those processing sensory information. We report here the discovery of a previously uncharacterized physiological inhibitor of enkephalin-inactivating zinc ectopeptidases in humans, which we have named Opiorphin. It is a QRFSR peptide that inhibits two enkephalin-catabolizing ectoenzymes, human neutral ecto-endopeptidase, hNEP (EC 3.4.24.11), and human ecto-aminopeptidase, hAP-N (EC 3.4.11.2). Opiorphin displays potent analgesic activity in chemical and mechanical pain models by activating endogenous opioid-dependent transmission. Its function is closely related to the rat sialorphin peptide, which is an inhibitor of pain perception and acts by potentiating endogenous mu- and delta-opioid receptor-dependent enkephalinergic pathways. Here we demonstrate the functional specificity in vivo of human Opiorphin. The pain-suppressive potency of Opiorphin is as effective as morphine in the behavioral rat model of acute mechanical pain, the pin-pain test. Thus, our discovery of Opiorphin is extremely exciting from a physiological point of view in the context of endogenous opioidergic pathways, notably in modulating mood-related states and pain sensation. Furthermore, because of its in vivo properties, Opiorphin may have therapeutic implications.

Variable coding sequence protein A1 as a marker for erectile dysfunction

OBJECTIVE

To investigate whether variable coding sequence protein A1 (Vcsa1) is down-regulated in rat models of diabetes and ageing, and to investigate the role of Vcsa1 in erectile function, as Vcsa1 is the most down-regulated gene in the corpora of a rat model of neurogenic erectile dysfunction (ED).

MATERIALS AND METHODS

Quantitative reverse-transcriptase polymerase-chain reaction was used to determine Vcsa1 expression in the corpora of rats in three models of ED, i.e. streptozotocin-induced diabetes, retired breeder (old), and neurogenic (bilaterally ligated cavernosal nerves), and in control rats. To confirm a physiological role of Vcsa1 in erectile function, we carried out gene transfer studies using a plasmid in which Vcsa1 was expressed from a cytomegalovirus promoter (pVAX-Vcsa1). This plasmid was injected intracorporally into old rats, and the effect on physiology of corporal tissue was analysed by intracorporal/blood pressure (ICP/BP) measurement and histological analysis, and compared with the effects of a positive control plasmid (pVAX-hSlo, which we previously reported to restore erectile function in diabetic and ageing rats) and a negative control plasmid (pVAX).

RESULTS

In each rat model of ED there was a significant down-regulation of the Vcsa1 transcript of at least 10-fold in corporal tissue. Remarkably, intracorporal injection with 80 microg pVAX-Vcsa1 caused priapism, as indicated by visible prolonged erection, histological appearance, and elevated resting ICP/BP. Lower doses of pVAX-Vcsa1 (5 and 25 microg) increased ICP/BP over that in untreated controls.

CONCLUSION

These results show that Vcsa1 has a role in erectile function and might be a molecular marker for organic ED. The role of Vcsa1 in erectile function suggests that it could represent a novel therapeutic target for treating ED.

Androgen regulation of SMR2 gene expression in rat submandibular gland: evidence for a graded but not a binary response

Expression of SMR2, a member of the gene family encoding salivary glutamine/glutamic acid-rich proteins, is regulated by androgens in rat submandibular gland acinar cells. To further characterize SMR2 regulation, we analyzed SMR2 expression during submandibular gland postnatal development and rat puberty at both a global and a single-cell level. Using in situ detection of mature and primary SMR2 transcripts, we show that SMR2 expression is heterogeneous among acinar cells. However, only one cell population with various amounts of mRNAs can be defined. The number of high-expressing cells increases in males during puberty and in females up to 6 weeks of age, suggesting that some factor in addition to acinar differentiation might be important for SMR2 expression in female rats. Involvement of the beta-adrenergic system in regulating SMR2 expression was tested in rats exposed daily to isoproterenol for 4 days. Under these conditions we found an increase in SMR2 expression in female rats, associated with an increase in SMR2 mRNA levels in most acinar cells. This suggests that a signaling cascade, elicited by beta-adrenergic stimuli, might act in concert with androgens to regulate SMR2 expression.